Probing faint radio activity from cores to filaments in two z=2.24 protoclusters with uGMRT

We present deep 1.26,GHz radio continuum observations of the two z=2.24 protoclusters BOSS1244 and BOSS1542 with the upgraded Giant Metrewave Radio Telescope (uGMRT) to investigate the radio emission of their member galaxies and its possible environmental dependence. Among 187 and 105 Hα emitter (HAE) members in BOSS1244 and BOSS1542, we identify ten and two robust radio counterparts, respectively, together with five potential counterparts from forced photometry. Two HAEs and the massive quiescent galaxy QG1 in BOSS1244 show strong radio excesses relative to their Hα-based star formation rates (SFRs) and are identified as strong radio-excess AGN candidates. Median stacking of the remaining 173 and 102 radio-undetected HAE members yields positive signals at 2.8σ and 3.2σ in BOSS1244 and BOSS1542, respectively. The stacked radio luminosities are consistent with those expected from the median Hα-based SFRs, indicating that star formation can account for the average faint radio emission. After excluding the robust radio counterparts, we further divided the HAE members by the projected distance from QG1 in BOSS1244 and from the filament spine in BOSS1542. The largest stacked radio luminosities are found toward the denser regions in both systems, but the differences are not statistically significant, and stellar mass shows no significant dependence on environmental distance. These results identify strong radio-excess AGN candidates among the individually detected members, while the faint HAE population is on average consistent with radio emission from star formation. The similar environmental ordering in the two protoclusters is suggestive but remains tentative. Deeper radio observations at multiple frequencies and higher angular resolution are required to determine whether this apparent trend reflects weak AGN activity or variations in radio emission associated with star formation.